As summer vacations end and the kids go back to school, resorts, hotels and airlines gear up to promote fall deals. Known as a "shoulder" season that follows the busy summer months, fall can be a great time to take advantage of cooler temperatures and travel bargains. But before you sign up for your next trip, be aware of the hidden costs that sometimes crop up and send your vacation spending soaring. (To help you avoid spending extra on a vacation, read The Easy Way To Stay On Budget On Vacation.)

TUTORIAL: Budgeting Basics

Resort fees.
Some of the best bargains can be offered at a resort community that offers golf, tennis and swimming in the warmer months and skiing in the winter. While greens fees and lift tickets are expected, you may think you are getting away with a bargain if you plan to spend your time relaxing by the pool or strolling around the grounds. But even if you plan to avoid the more costly resort amenities, you may be charged a "resort fee" or a fee for the fitness center or even the business center regardless of whether you use those facilities. Some hotels bill $5 or $10 per day for these amenities and others even charge a dollar or two per day for grounds keeping fees and towels at the swimming pool.

Hotel fees.
Plenty of hotels offer Internet connections in your room and offer to hold your bags if you need to check out before its time to head to the airport, but most will charge you a fee for these services. Some amenities that may seem free, like the bottle of water on the dresser or the newspaper delivered to your door will actually be charged to you on your final bill even if you didn't ask for them. Energy surcharges, fees for the shuttle bus from the airport and charges for just moving items around in the mini-bar can also show up on your bill.

Rental car fees.
If you are quoted a per-day fee for a rental car, it may seem like a bargain, but you should ask for a quote that includes all fees, taxes and surcharges so you know the true cost upfront. Rental car companies always offer insurance, but you are usually covered for rental car accidents by your credit card company and your car insurance. Call your company to check this out before you rent a car and you can save $20 or $30 per day. Late return fees can go as high as a full additional day of fees for a one-hour late return. Filling up the tank on your own is usually cheaper than letting the rental car company do it for you. (To learn more about renting a car, see 8 Things You Need To Know Before Renting A Car.

Airline fees.
While a bargain airfare may entice you to book a trip this fall, make sure you remember that you'll be expected to pay for a few extra items along the way. If you book by phone rather than on the airline website, you'll often be charged $20 or more for the privilege of talking to an airline representative. Depending on the airline, you'll be charged for checking one or more bags, often as much as $25 to $50 per bag. If your bag is over 50 pounds, you could pay as much as $80 or more each way. If you want a snack or a meal on the plane, you'll need to pay $5 or $10 or more, along with paying for any alcohol. Other airlines will charge you $10 to $30 or more for the privilege of boarding early, and many charge extra for the more desirable seats, such as aisle seats or a place in the exit row. Watch out when you check in online, because some of these fees can pop up and require you to decline the service to avoid payment.

Taxes turn up everywhere and in every season on travelers. You'll be taxed on your plane ticket and on your rental car, but you may feel the tax bite most on your hotel room. USA Today reported that hotel tax rates are on the rise in many cities. Lodging taxes averaged 13.73% on a national basis when you combine city, county and state taxes, and range from 10% to nearly 18%.

The Bottom Line
Whether you are planning an autumn trip to admire the foliage or a quick escape to the beach in a warmer climate for a return to summer weather, make sure you get the complete picture of what your bill will be like before you book. (To help protect your hard-earned dollars while traveling, check out Travel Tips For Keeping You And Your Money Safe.)